Both stationary undesirable fluids and materials may adversely affect commercial and residential land and structures. Both the land and structures may be adversely affected by the action of undesirable fluids and materials in, against and under structures. The undesirable fluids and materials also may contaminate the land. Structures may be adversely affected by seepage of undesirable fluids and materials beneath structures because, to the extent that seepage occurs in the vicinity of concrete and other materials used to construct foundations and other components of structures, the structure may be adversely affected as more particularly described below. In addition, undesirable fluids and materials may erode open land, as well as land on which structures are constructed, adversely affecting the use, value and utility of land and structures.
Since time immemorial, a common way to both transport water and to drain undesirable fluids and materials has been the use of ditches. The term “ditch” as used in this document means any excavation dug in the earth, or any structure partially or completely installed above earth, that may be referred to as a drain, channel, canal or acequia, whether lined or unlined, that usually but not always relies on principles of gravity and gravity flow to transport fluids such as water along descending elevations of the ditch.
Since the introduction and use of combinations of Portland cement and aggregate to the construction industries, concrete-lined ditches have been used to transport fluids such as water through ditches. Examples of such installations of concrete lined ditches are shown in FIGS. 1A–1B. Concrete seemed useful because it could be formed to fit varying slopes and directions of earthen ditches. Water, however, whether freestanding or moving, that seeps into and against concrete in concrete-lined ditches often adversely affects commercial and residential structures. Examples are shown in FIGS. 1C–1D. Concrete, unfortunately, has inherent brittle tendencies to crack, and is difficult to repair in remote and challenging terrain due in part to the weight of concrete and the weight of hauling and installing equipment and vehicles. Concrete repair also may disrupt landscapes due to heavy equipment needed. Accordingly, corrosion mitigation systems, particularly in connection with concrete, are a significant goal in the construction industries.
Concrete drains manufactured from Portland cement and various aggregates are subject to deleterious damage caused at least in part by alkali-silica reactivity (“ASR”). ASR is a chemical reaction between Portland cement concrete and aggregates that in some environments, and under some conditions, may cause severe damage to concrete ditches. ASR also may expedite other reactions that in turn cause damage, such as freeze-thaw or corrosion related damage. The phenomenon has been recognized since at least 1940, but neither the mechanisms of ASR, nor solutions, yet are clearly understood.
It is known, however, that deterioration of a concrete structure such as a concrete-lined ditch is due at least in part to water absorption by a gel that forms in concrete. The term “gel” as used in connection with concrete fabrication refers to a naturally occurring silica gel that is a colloidal silica resembling course white sand, but has many fine pores, a condition that causes the gel to be extremely adsorbent. Soluble alkalis also are present in cement, and may be affected by undesirable moisture. Vulnerable sites in the silica structure may be attacked by fluid-induced activity, converting the silica to a silica gel that absorbs water or other fluids.
An important property of concrete is its tensile strength, or its ability to react to longitudinal stress. Liquids, however, are known to adversely affect tensile strength in concrete. If the tensile strength of concrete is exceeded, cracks will form and propagate from one or more alkali-silica reaction sites, weakening the concrete structure. Many if not all of these problems generally associated with ASR may be seen in concrete-lined ditches that have been constructed in situ for any length of time. In addition, concrete becomes ever more expensive, and is difficult to install and maintain.
Suggested alternatives to concrete-lined ditches or drains are apparatus manufactured of one or more metals. Metal ditch liners, however, have proven to be neither cost effective nor durable in the presence of moving or stationary fluids, particularly undesirable fluids and materials.
A need exists in the industry, therefore, for a new, useful interlockable drainage system capable of removing undesirable fluids and materials from both open land as well as land adjacent to structures, in which the components of the interlockable drainage system may be installed in unlined ditches as well as over existing concrete-lined ditches or even other ditch liners; a system that is not susceptible to alkali-silica reactivity or to other deleterious affects associated with concrete; and a system that is flexible, light-weight, long-lived, easily installed, easily maintained or replaced, and inexpensive both to install and to maintain.